Security
Processed locallyJWT Signature Verifier
Verify HS256 JWT signatures and inspect expiration and not-before claims.
Tool options · presets, sharing & more
Presets & sharing: options only, never files, text or passwords. Undo/redo: editable form values, not file selection or generated results.
How to Use JWT Signature Verifier
Enter the token or Base32 secret, or choose the asset for an integrity hash.
Select the supported algorithm and required parameters.
Run the operation and inspect the signature, expiry, or hash result.
Use the result only within the tool's stated validation limits.
What This Tool Does
Verify HS256 JWT signatures and inspect expiration and not-before claims. Only HS256 is supported. The signature check does not validate issuer, audience, or authorization rules. Unsigned and unsupported algorithms are rejected.
Common Use Cases
This tool processes files and input in this browser tab. Its processing code does not upload them to a server. Loading this page and fetching uncached app files uses an internet connection. Optional usage analytics requires your consent and excludes input, filenames, passwords and generated content. Form undo history and result transfers stay in session memory. Explicitly saved presets contain approved settings only.
Offline use is not verified for this tool. Keep an internet connection available to load its page, code and any additional dependencies.
Frequently Asked Questions
What should I check before using the result?
Only HS256 is supported. The signature check does not validate issuer, audience, or authorization rules. Unsigned and unsupported algorithms are rejected.
Are my files or inputs uploaded?
No. This tool processes selected files and entered data locally in your browser. Only the page and its supporting code are downloaded.
Does this tool work offline?
Offline use is not verified for this tool. Keep an internet connection available to load its page, code and any additional dependencies.